Our research program represents an interdisciplinary approach to fundamental problems in cellular immunobiology. The research focuses on the analysis of molecules and molecular assemblies involved in control and recognition both at the surface and within cells of the immune system. Our studies are grouped in four major areas: 1) to examine various hypotheses on surface modulation and to characterize the molecules involved in transmembrane control; 2) to describe using biochemical techniques, the pathway by which cells are stimulated to undergo mitosis and to link events at the cell surface with the initiation of DNA synthesis; 3) to study the role of molecules on the surfaces of cells of the immune system in specific recognition events by examining the function of murine transplantation (H-2) antigens in immune surveillance against virally infected cells and tumor cells, to characterize chemically the H-2 antigens and beta2-microglobulin, and to define the genetic controls that regulate the expression of molecules on the cell surface during fetal development; and 4) to describe important interactions at the surfaces of immune cells by using X-ray crystallographic and electron microscopic techniques to examine carbohydrate-binding proteins and beta2-microglobulin.